Conglog, seen from the bwlch between Cwmorthin and the Rhosydd plateau.

​The Conglog mine seems always to have been overshadowed by it's more powerful neighbours. Literally, in the case of the mighty Rhosydd workings to the south west, while Cwmorthin, down the valley, held the door keys to it's route to market, the only economic way out of the cwm.

These days, most people hurry by the four strange daylight chambers of the mine on their way to Rhosydd, or to the summit of Moelwyn Mawr. We usually stop to have our lunch near the weigh house on floor C and are often entertained by an endless cavalcade passing by. Walkers fully kitted out, others in flip flops. Two guys walking up bouncing a football. People with dogs. A sweating, galloping army platoon. Parties of children doing outdoor activities. None ever seem to give the place a second glance.

Conglog seen from the Rhosydd Quarry managers house

Yet, Conglog is an impressive sight, with rows of ruined buildings, a mill (converted to a sheep pen), the aforementioned twlls in the side of the hill and large slate tips. Not to mention the craziest set of launder pillars. To understand, perhaps we need to go back in time a little.

The beginningsThe quarry was opened in 1854, when it was the subject of a temporary permission to extract minerals order, or “take note” from Cwmorthin Uchaf farm, belonging to Lord Harlech. One of the partners of the enterprise was Robert Roberts, a surgeon at the Oakeley Quarry hospital at Rhiwbryfdir, and it is assumed that he provided the capital for the venture. By 1868 a 21 year lease had been taken out on the land.

Meanwhile, nearby Rhosydd had been extracting slate up the hill since 1853 and their spoil tips and buildings began to encroach on the Conglog sett. They, Rhosydd, had built their manager's house, Plas Cwmorthin, on land to the east of Conglog, just outside the leased territory. But in a later, possibly aggressive move, they built a barracks on Conglog land, next to where the mill would be in 1865/6. From then on, there would be frequent disputes about land . Rhosydd had also built stables near the Conglog mill. From this distance in time, it all looks a little like intimidation. Standing at the launder pillars near the Conglog mill and gazing up at the vast floor 9 tips of Rhosydd there is certainly a feeling of “big brother”.​

Intimidation? The Rhosydd tips tower over a Conglog launder pillar.

And yet...Conglog were to have the last laugh.

Cwmorthin had stood in the way of Rhosydd when they had wanted to take their produce down to the Ffestiniog railway. The wayleaves and tonnage charges proposed by Cwmorthin were prohibitive, forcing Rhosydd to build the famous, vertiginous incline down to Cwm Croesor.

​But when Conglog suggested the building of a tramway down to the railhead at Tan-y-Grisiau in 1873, Cwmorthyn rolled over and let them do it, much to the chagrin of big brother up the hill. Things had changed at Conglog, though. The quarry had gone through several rounds of personnel and that year was managed by a Devon man, W H B Kempe. It is speculated that he was related by marriage to the manager at Cwmorthin, Joseph F Sims, also a Devonian. Perhaps it was a case of blood being thicker than water, who knows? The upshot is that we were left the lovely tramway from the old Cwmorthin mill all the way to Conglog to walk on, bounded by those beautiful slate slab fences.

Of course, the bad feeling hadn't ended, there were numerous disputes over water rights for powering the machinery - and Rhosydd built a stables near the Conglog mill. Conglog eventually won the right to use Tan yr Allt, the Rhosydd barracks built next to their mill, but that option was never used.

Rhosydd did tip over one of Conglog's water sources, the Bwlch Rhosydd stream; as a result, in 1903, they won the exclusive right to water from Llyn Conglog. I wonder if this is why the mysterious waterwheel pit and bastion at the bwlch was built, but never used by Rhosydd? We will never know.

Launder buttresses and "Crawiau Llechi" (slate slabs)

UndergroundWhile not as spectacular as Rhosydd or Cwmorthin, Conglog does possess some beautiful chambers, cathedral-like in their size and acoustics. Not that I recommend singing in the chambers as there have been some mighty falls, like the dagger-shaped slab of slate that buried itself in the floor of chamber B4. The enormous lump of slate (the size of a single decker bus) at the back of B4 must also have made a bang when it landed. I've been told of men having burst eardrums and broken ribs from being in a chamber when a major collapse happens, and I can believe it. Luckily, nothing fell on the several occasions we were underground.

Access to the level B chamber system at Conglog is past a perilous looking collapse, held up by a prop of timber and some dubiously stacked rocks, most too heavy to lift by one man. We squeezed past this with great caution, before entering into the airy space of chamber B4, where the roof rises 30 metres above, feint light coming in from a roofing shaft high at the end. An adit drives further into the hill, expoiting the north vein. The only chamber to work the back vein, the one worked by the Ffestiniog slate quarries such as Maenofferen, is near the adit portal, coming off the level B tunnel before the collapse. A further three chambers lie along the line of the adit, running east-west. The adit then drives 249 metres further into the hill, although why, when the North Vein had obviously been found, I don't understand.

The level B adit, with an entrance to the back vein chamber (B1), the only one to exploit the back vein.

​As far as we can find out, the level B workings were driven by Devon miners in 1872, under a sub-lease from Robert Roberts, the main quarry lessee and a surgeon in the Oakley Hospital, whose men were busy on level C. The rent charged enabled Roberts to pay his rents from the landowner. Later on, the quarry was worked by a consortium of local men, trading as the Glyn Ffestiniog Slate Company until 1910, when the quarry closed. It seems that B6 was the last chamber to be worked, and rather poignantly, a loaded rubbish wagon sits inside, waiting in vain to be trundled outside and tipped.

Surface remainsThe most obvious features are the launder pillars, leaning because they were built on a foundation of slate waste. They were shored up several times, using the skills on tap from the quarry craftsmen. They seem now like rather fine sculptures, superior to those contrived examples in Blaenau Ffestiniog near the FR station.The incline, cut by the later Rhosydd quarry track, was constructed in the 1870s and is at 30 degrees, becoming shallower as it reaches the mill. The mining Journal in 1874 states that Mill and incline are the work of John Edwards of Ffestiniog, manager between 1874-79.The archaeology of the mill, as I mentioned, has been greatly confused by use as a sheep pen, but we know that it was equipped with a 30 foot diameter waterwheel. A list from the 1891 sale has 2 planing tables, 8 sawing tables, and a dressing machine. There is also a smithy and stockyard.

Further up towards the incline head are the remains of a weigh house and a drum house. There does not seem to be a magazine anywhere, which is curious.

The weigh house at the top of the incline

In conclusion, I don't think Conglog is a cinderella. It is as fascinating and intriguing as any other quarry in the cwm and rewards a careful explore, bearing in mind that it is a very dangerous and delicate place. The adits are wet, and SRT will be required for exploration of some of the less obvious nooks and crannies.

​The depiction of a mine or site does not indicate that access is possible- permission should be sought before entering any private land.Underground exploration should not be undertaken unless properly equipped and with at least one experienced member of the party.